8/11/2019 MIMO Toolbox
1/25
MIMO Toolbox
For Use with MATLAB
Oskar Vivero
8/11/2019 MIMO Toolbox
2/25
About the toolbox
The MIMO Toolbox is a collection of MATLABfunctions and a GUI. Its purpose is to
complement the Control Toolbox for MATLABwith functions capable of handling the
multivariable input-output scheme. All the results and examples except for example1.1.2.1 were obtained with the MIMO Toolbox and were corroborated with the
bibliography.
April, 2006
Installation
The installation is straightforward just copy the directory Mimotools and add the path
to the MATLABsearch path.
See path, in the MATLABdocumentation for more information.
Requirements
The MIMO Toolbox was created in Matlab 7.1 (R14) SP3, and requires the Symbolic
and Control Toolboxes.
Contact
Oskar Vivero
8/11/2019 MIMO Toolbox
3/25
Contents
1. Theory behind the functions
1.1.SISO Systems
1.1.1. Feedback Basic Concepts
1.1.2. Nyquists Stability Criterion
1.2.MIMO Systems
1.2.1. Poles and Zeros of a MIMO System
1.2.1.1. Smith-McMillan Transformation1.2.2. Stability of MIMO Systems
1.2.2.1. Generalized Nyquists Stability Criterion
1.2.3. Treating a MIMO System with SISO techniques
1.2.3.1. Coupling degree and pairings of inputs and outputs
1.2.3.2. Nyquists Arrays and Gershgorin Bands
1.2.3.3. Relative Gain Array (RGA)
1.2.3.4. Individual Channel Design (ICD)
2.
Function Reference
2.1.The Symbolic Transfer Function
2.2.
Function Description
2.2.1.
tf2sym2.2.2. sym2tf
2.2.3. ss2sym
2.2.4. smform
2.2.5. rga
2.2.6. nyqmimo
2.2.7. m_circles
2.2.8. icdtool
2.2.9. gershband
2.2.10.arrowh
3. References
1
1
1
2
4
4
47
7
10
10
10
11
12
14
14
14
1415
16
16
17
17
19
19
20
21
22
8/11/2019 MIMO Toolbox
4/25
MIMO Toolbox
- 1 -
1. Theory behind the functions
The aim of this chapter is to introduce the MIMO control theories so that one can
understand both, the algorithm behind each function and its proper use. This chapter is
only intended to provide a brief description of such theories and its recommended that
the user refers to the bibliography listed at the end of this document.
1.1 SISOSystems
1.1.1 Feedback Basic Concepts
Assuming a lineal process that is time-invariant whose behavior is defined by lineal
differential equations with constant coefficients:
1 2 1 2y a y a y b u b u
+ + = +
where ( )y t is the output signal and ( )u t is the input signal, its possible to obtain a
transfer function by applying the Laplaces Transform
( )
( ) ( )
( )
( )1 2
2
1 2
Y s N s b s bG s
U s D s s a s a
+= = =
+ +
( )
( )
If 0 then is defined as a zero.
If then is defined as a pole.
Z Z Z
P P P
s s G s s
s s G s s
= =
= =
If ( )G s is rational, usually ( )D s determines the dynamic characteristics of the system,unless there exist cancellations between ( )N s and ( )D s .
Let ( )H s and ( )G s be two transfer functions
The stability of the system in a closed-loop configuration is given by ( ) ( )1 G s H s+ ifand only if there is no cancellation of instabilities. For any design, its possible to
verify its stability by finding the singularities of ( )CLG s . If any of the singularities is
located in2
+ or near the imaginary axis, its almost impossible to determine the
modifications needed on either ( )G s or ( )H s to avoid the location of the singularities.
The Nyquists stability criterion provides a tool for solving the problem
( ) ( )
( ) ( )1CL
G sG s
G s H s=
+
8/11/2019 MIMO Toolbox
5/25
MIMO Toolbox
- 2 -
1.1.2 Nyquists Stability Criterion
The system in a closed-loop configuration is stable if and only if the trajectory of the
Nyquist diagram of ( ) ( )G j H j from < < surrounds the point ( )1,0 in a
counter-clockwise direction as much times as ( ) ( )G s H s has unstable poles.
Theorem suppose that a function ( )f z is meromorphic in a simply connected domain
D, and that C is a simple closed positively oriented contour in D such that ( )f z does
not contain any singularities. Then
( )
( )
'1
2f f
f zN dz Z P
i f z= =
where Nis the winding number,f
Z is the number of zeros inside the contour andf
P
is the number of poles inside the contour.
Example 1.1.2.1
The image of the circle of radius 2 centered at the origin under ( ) 2f z z z= + is the
curve ( ) ( ) ( ) ( ) ( )( ), 4cos 2 2cos , 4sin 2 2sing x y t t t t = + + . Note that the curve ( ),g x y winds up twice around the origin. We check this by computing
( )
( )
0 1
0 1
2 2
'1 ; Singulatiries at 0 and 1
2
2 1 2 1
Res Res 2
C
z z
f zN z z
i f z
z z
N z z z z
= = =
+ + = + = + +
Having defined N, its important to define a useful contour for the stability analysis.
Its possible to know from the root locus analysis and the time response that the
unstable poles are at the right side of the S-plane. Since the zeros of the open loop
system are the poles of the closed loop system, well focus on finding the unstable zeros
through Nyquist frequency analysis. The contours that well consider are:
8/11/2019 MIMO Toolbox
6/25
MIMO Toolbox
- 3 -
Example 1.1.2.2 [4] pp. 620
Draw the Nyquist contour and diagram of ( )( )( ) ( )
500
1 3 10G s
s s s=
+ + +
Once the stability of a system has been defined through the Nyquists diagram, therobustness of the system can be defined by two quantities, the gain and phase margins.
Gain margin ( )MG - the change of gain in open loop needed to obtain a phase shift at
180 that turns the system unstable.
Phase margin ( )M - the phase shift in open loop needed to turn the system unstable
with a unit gain.
8/11/2019 MIMO Toolbox
7/25
MIMO Toolbox
- 4 -
1.2 MIMOSystems
The basic description of a multivariable system is through a transfer function matrix
(TFM), whose elements ,i jg represent the i-est output with the j-est input. The
elements,i j
g are individual transfer functions.
1.2.1 Poles and zeros of a MIMO system
The poles and zeros of multivariable systems can be defined in several (not all
equivalent) ways, but the definitions that yield the most significant consequences are
given by [1]:
The zeros of a transfer function matrix ( )H s , are the roots of the (nonzero) numerator
polynomials ( ){ }i s in the Smith-McMillan form of ( )H s . The Smith-McMillan form
allows us to give a physical interpretation of the zeros. If Zs is a zero, then the Smith-McMillan form of ( )H s will lose rank at Zs s= .
The poles of a transfer function matrix ( )H s , are the roots of the denominator
polynomials in the Smith-McMillan form of ( )H s .
1.2.1.1 Smith McMillan Transformation
Given a rational matrix ( )H s
( ) ( )
( )
N sH s
d s
=
where ( )d s is the monic least common multiple of the denominators of ( )H s
Then ( ) ( ) ( )d s H s N s= is a polynomial matrix, so that we can write,
( ) ( ) ( ) ( ) ( ) ( )1 2d s H s N s U s s U s= =
8/11/2019 MIMO Toolbox
8/25
MIMO Toolbox
- 5 -
where the ( ){ }iU s are unimodular matrices and ( )s is in Smith form
( ) ( ) ( ) ( )
( )
( )
( )
( )
( )
( )
( )
1 1
1 2
i
i i
i
s sU s H s U s diag
d s d s
s s
d s s
= =
=
where ( ) ( ){ },i is s are coprime, 1, ,i r=
and r is the (normal) rank of ( )H s
Then we can write
( ) ( ) ( ) ( )1 2H s U s M s U s=
where ( )M s is the Smith-McMillan transformation of ( )H s given by
( )
( )
( )0
0 0
i
i
sdiag
M s s
=
Smith Form
For any p m polynomial matrix ( )P s we can find elementary row and column
operations, or corresponding unimodular matrices ( ) ( ){ },U s V s such that
( ) ( ) ( ) ( )U s P s V s s=
where
( )
( )
( )
( )
0
0
0 0 0
the (normal) rank of
i
r
s
ss
r P s
=
=
and the ( ){ }i s are unique monic polynomials obeying a division property
( ) ( )1 , 1, , 1i is s i r + =
Moreover, if( ) ( )the gcd of all minors ofi s i i P s =
then
( ) ( )
( ) ( )0
1
, 1i
i
i
ss s
s
= =
The matrix ( )s is called the Smith form of ( )P s
8/11/2019 MIMO Toolbox
9/25
MIMO Toolbox
- 6 -
Example.1.2.1.1 [1] pp. 444-446
Find the poles and zeros of
( )( ) ( )
( )
( ) ( )
2
2 2 2 2
11
1 2 1 1
s s sG s
s s s s s s
+ = + + + +
SolutionGiven
( )( )
( )1
G s N sd s
=
where
( ) ( ) ( ){ } ( ) ( )
( )
( )
( ) ( )
2 2 2 2
2
2 2
1 2 1 2
1
1 1
d s lcm s s s s
s s s
N s s s s s
= + + = + +
+
= + +
Finding ( )s in Smith form:
( )
( ) ( ) ( ) ( )( )
( ) ( ) ( )( )( ) ( )
( ) ( ) ( ) ( )
0
2 2 2
1
23
2
1 1
22
2 2
1
gcd , 1 , 1 , 1
gcd 1 2
1 2
s
s s s s s s s s s
s s s s
s s s
s s s s s
=
= + + + =
= + +
= =
= = + +
Therefore
( )
( )
( ) ( ) ( )
2 2
2
00 1 2
00 02
i
i
ss
diag s sM s s
s
s
+ + = =
+
The poles are defined as
( ) ( ) ( ) ( ) ( ) ( )[ ]
2 2
1 2 1 2 2 0
1 1 2 2 2
p s s s s s s
p
= = + + + ==
The zeros are defined as
( ) ( ) ( )
[ ]
3
1 2 0
0 0 0
z s s s s
z
= = =
=
8/11/2019 MIMO Toolbox
10/25
MIMO Toolbox
- 7 -
1.2.2 Stability of MIMO Systems
Having defined a tool in order to obtain the poles and zeros of a MIMO system, its
necessary to define if the system is stable. This can be achieved by the generalized
Nyquists stability criterion, which is an adaptation from the Nyquists stability criterion
for SISO systems.
1.2.2.1 Generalized Nyquists Stability Criterion
Let ( )G s be a rational TFM, assuming that it has no cancellations between poles and
zeros. Let Kbe a compensator with a negative feedback loop, that is
I ;K k k=
Let the ( )det I KG s+ have P poles and Zzeros in the right hand plane (RHP), then
like in SISO systems
( ) ( )arg det I 2KG s Z P + =
where arg is the change of phase given by salong the Nyquists contour. In order to
obtain stability in a closed loop, it is required that the diagram mapped by
( )det I KG s+
surrounds the origin Ptimes.
As a difference from the SISO case, the Nyquist diagram of each kof interest must be
obtained.
If ( )i s is an eigenvalue of ( )G s , then ( )ik s is an eigenvalue of ( )KG s , and
therefore, ( )1 ik s+ is an eigenvalue of ( )I KG s+ . Then
( ) ( )det I 1 ii
KG s k s+ = +
and
( ) ( )arg det I arg 1 ii
KG s k s + = +
Therefore, the stability in a closed loop system can be inferred by the number of wind
ups to the point ( )1,0 given by the Nyquist diagram of ( )ik s . The Nyquist diagram
of ( )i s are known as the characteristic graphs of ( )G s .
8/11/2019 MIMO Toolbox
11/25
MIMO Toolbox
- 8 -
Theorem If ( )G s has right hand plane poles (RHPP), P, given by the Smith-McMillan
transformation, then the closed loop with negative feedback is stable if and only if the
characteristic graphs of ( )KG s surround the point ( )1,0 P times in a counter-
clockwise direction, assuming that there was no cancellations of instabilities.
Example 1.2.2.1 [2] pp. 61Find the values of 0k> in order to keep ( )G s from becoming unstable
( )( )( )
11
6 21.25 1 2
s sG s
ss s
=
+ +
Solution
Its easy to verify that the open loop poles of ( )G s are [ ]1 2P = , therefore, in
order to maintain the closed loop system stable, we must ensure that the number of
surroundings of the characteristic graphs of ( )G s is equal to zero.Assuming 1k= , then
( )
( )( )
( )( )
2
1
2
2
det I 0
2 2 3 24 1
5 3 2
2 2 3 24 1
5 3 2
KG s
s s
s s
s s
s s
= =
+ + + + = = + + +
From the eigenvalues of ( )G s , its possible to obtain the Generalized Nyquist Diagramwhen 1k =
8/11/2019 MIMO Toolbox
12/25
MIMO Toolbox
- 9 -
From the diagram its possible to obtain the critical points in which we can calculate the
values of k, in order to keep the system stable. Knowing that the critical points are in
0.8 and 0.4 , therefore
1 11.25 , 2.5
0.8 0.4k k
< = > =
This can be proven by setting the values of kequal to 1.25 and 2.5 and obtaining the
Nyquist Diagram.
8/11/2019 MIMO Toolbox
13/25
MIMO Toolbox
- 10 -
1.2.3 Treating a MIMO system with SISO techniques
1.2.3.1 Coupling degree and pairing of inputs and outputs
Given the coupling degree of a MIMO system, its possible to apply certain SISO
techniques for designing controllers. The degree of coupling can be found by several
techniques, such as the Nyquists arrays and the Gershgorin bands, the relative gain
array (RGA), and the individual channel design (ICD). In some cases, it is possible tocross couple inputs and outputs in order to obtain a less coupled system.
1.2.3.2 Nyquists Arrays and Gershgorin bands
The Nyquists array of a TFM ( )G s , is an array of graphs, where the i, j-est graph is the
Nyquist Diagram of ,i jg .
Gershgorin Theorem let Z a n n complex matrix. Then, the eigenvalues of Z fall
on the union of circles with center at,i i
z with radius
,1
m
i jj
j i
Z=
and on the circles with center at,j j
z with radius
,1
m
i ji
i j
Z=
Gershgorin Bands
Over the Nyquists diagram of ( ),i ig s , on each point, we super impose a circle of
radius
( ) ( ), ,1 1
orm m
i j j ii i
i j i j
g j g j = =
The bands obtained in this way are known as the Gershgorin Bands.
By the Gershgorin theorem its possible to know that the bands trap the unions of theNyquist diagram. More over, its possible to demonstrate that the bands occupy
different regions, therefore there will be as many Nyquists diagrams trapped in a region
as many Gershgorin bands are there.
Then, by counting the number of wind ups that the Gershgorin bands do around the
point ( )1,0 , its possible to determine the stability of the MIMO system.
8/11/2019 MIMO Toolbox
14/25
MIMO Toolbox
- 11 -
If the Gershgorin bands are thin and exclude the origin, it is said that ( )G s is
diagonally dominant which can be interpreted as a decoupled system.
Example 1.2.3.1 [3] pp. 657
Find the Gershgorin bands of
( )2
2 2
2 0.1
13 2
0.1 6
2 1 5 6
ss sG s
s s s s
++ +
= + + + +
From the graphs above, its possible to observe that the system is stable and highly
decoupled. Therefore, it can be managed as two independent SISO systems with small
disturbances due to the small coupling degree.
1.2.3.3 Relative Gain Array (RGA)
To measure the degree of coupling or interaction in a system, the concept of relative
gain array can be used. For an arbitrary n n matrix A, it is defined as
( ) ( )1RGA .*T
A A A=
The RGA matrix has a number of interesting properties
The sum of the elements of any row or column is always 1 RGA is independent of any scaling
The sum of the absolute values of all elements in ( )RGA A is a good measure of
As true condition number, i.e., the best condition number that can be achieved
in the family 1 2D AD , where iD are diagonal matrices.
Permutation of the rows or columns of A leads to permutations of the
corresponding rows or columns of ( )RGA A .
8/11/2019 MIMO Toolbox
15/25
8/11/2019 MIMO Toolbox
16/25
MIMO Toolbox
- 13 -
( )
( )
12 21
11 22
1
i ii
i
i ii
g gs
g g
k gh s
k g
=
=+
The MSF ( )s is of great importance inside the ICD analysis framework, since it is
capable of [6]
Determining the dynamical characteristics between each input and each output
It has an interpretation in the frequency domain
Its magnitude quantifies the amount of coupling between the channels
It can determine the transmittance zeros of the system from ( )1 s
( ) 1s = determines the non-minimum phase conditions
Its closeness to the point ( )1,0 its a key point in determining the robustness ofthe system
Robustness Conditions
In order to obtain a design that provides a channel that is robust and stable, the
following conditions should be satisfied
1. ( )s should not be close to the point ( )1,0 for all
2. ( ) ( )is h s shall be robust
3. ( ) ( )i iik s g s shall be robust
The interaction between the discarded inputs and outputs can be observed from
( ) ( )
( ) ( )
( ) ( )
1
1
ij
i j j
jj i
g sY s h s R s
g s C s=
+
8/11/2019 MIMO Toolbox
17/25
MIMO Toolbox
- 14 -
2. Function Reference
The aim of this chapter is to give a brief description of the functions used in the MIMO
toolbox. For the users that are new to the Matlab environment it is recommended to
review the getting started documentation.
2.1 The Symbolic Transfer Function
The Control Toolbox in Matlab posses an object class that describes a transfer function.
This model representation is numerical and its sensitive to floating point errors due to
arithmetic operations such as inversion. Also, from the LTI definition, the transfer
function class cannot handle nonlinearities such as square roots, trigonometric
functions, etc, since its only a rate in polynomial representation. Given such problems,
a symbolic conversion for transfer function has been developed, and its key to some of
the functions inside the MIMO toolbox. This conversion enables the user to handle the
transfer function and its operations as an algebraic problem, simplifying the
computational difficulties that may arise for the users without a computer sciencebackground.
2.2 Function Description
2.2.1 tf2sym
SyntaxG_sym = tf2sym(G)
Description
tf2sym performs the conversion from a numeric to a symbolic representation of atransfer function. The function is capable to deal with both SISO and MIMO models.
To be able to differentiate the type of transfer function, the symbolic transfer function is
represented with the Laplace operator p instead of s.
Example 1>> G=tf([1 2 3],[1 5 6 7])
>> G_sym=tf2sym(G);
>> pretty(G_sym)
2
3 + p + 2 p
-------------------
3 2p + 5 p + 6 p + 7
Example 2>> g11=tf([1 2],[1 2 1]);
g12=tf([1 -1],[1 5 6]);
g21=tf([1 -1],[1 3 2]);
g22=tf([1 2],[1 1]);
G=[g11 g12; g21 g22];
g=tf2sym(G);
pretty(g)
8/11/2019 MIMO Toolbox
18/25
MIMO Toolbox
- 15 -
[ 2 + p -1 + p ]
[ -------- ---------------]
[ 2 (p + 3) (2 + p)]
[ (p + 1) ]
[ ]
[ -1 + p 2 + p ]
[--------------- ----- ]
[(2 + p) (p + 1) p + 1 ]
2.2.2 sym2tf
SyntaxG = sym2tf(G_sym)
Description
sym2tf performs the conversion from a symbolic to a numeric representation of a
transfer function. As tf2sym, this function is capable of dealing with both SISO and
MIMO models. This conversion cannot handle nonlinearities since the numeric transfer
function class tf is not capable of dealing with the nonlinearities.
Example 1>> syms p
>> G_sym = (p^2 + 2*p + 3)/(p^3 + 5*p^2 + 6*p + 7);
>> G=sym2tf(G_sym)
Transfer function:
s^2 + 2 s + 3
---------------------
s^3 + 5 s^2 + 6 s + 7
Example 2>> g11=(p + 2)/(p^2 + 2*p + 1);
g12=(p - 1)/(p^2 + 5*p + 6);
g21=(p - 1)/(p^2 + 3*p + 2);
g22=(p + 2)/(p + 1);
g=[g11 g12; g21 g22];
G=sym2tf(g)
Transfer function from input 1 to output...
s + 2
#1: -------------
s^2 + 2 s + 1
s - 1
#2: -------------
s^2 + 3 s + 2
Transfer function from input 2 to output...s - 1
#1: -------------
s^2 + 5 s + 6
s + 2
#2: -----
s + 1
8/11/2019 MIMO Toolbox
19/25
MIMO Toolbox
- 16 -
2.2.3 ss2sym
SyntaxG = ss2sym(A,B,C,D)
Description
ss2symperforms the conversion from a state space representation to a symbolic transfer
function.
Example>> A = [0 1 0 0 0; 0 0 1 0 0; -2 -5 -4 0 0; 0 0 0 0 1; 0 0 0 -3 -4];
B = [0 0; 0 0; 1 0; 0 0; 0 1];
C = [1 2 1 9 3; 14 9 1 1 1];
D = [0 1; 0 0];
g=ss2sym(A,B,C,D);
pretty(g)
[ 1 p + 4]
[ ----- -----]
[ 2 + p p + 1]
[ ][ p + 7 1 ]
[-------- -----]
[ 2 p + 3]
[(p + 1) ]
2.2.4 smform
Syntax[M,poles,zeros] = smform(G)
Description
[M,poles,zeros] = smformcomputes the Smith-McMillan transformation, the poles
and zeros of a MIMO TFM. The algorithm obeys directly the theory specified on thesection 1.2.2.1 of this document by establishing an active link with the Maple kernel.
Example>> g11=tf([1 1],[1 3 2]);
g12=tf([1 4],[1 1]);
g21=tf([1 7],[1 2 1]);
g22=tf([1 2],[1 5 6]);
G=[g11 g12 ; g21 g22];
[M,poles,zeros]=smform(G);
>> pretty(M)
[ 1 ]
[------------------------ 0 ]
[ 2 ]
[(p + 3) (p + 1) (2 + p) ]
[ ]
[ 4 3 2 ]
[ p + 15 p + 86 p + 203 p + 167]
[ 0 --------------------------------]
[ p + 1 ]
8/11/2019 MIMO Toolbox
20/25
MIMO Toolbox
- 17 -
>> poles
poles =
-3.0000
-2.0000
-1.0000
-1.0000 + 0.0000i
-1.0000 - 0.0000i
>> zeros
zeros =
-5.3101 + 2.5439i
-5.3101 - 2.5439i
-2.1899 + 0.1460i
-2.1899 - 0.1460i
2.2.5 rga
SyntaxA=rga(G)
Description
rgacomputes the Relative Gain Array of a MIMO TFM. The algorithm obeys directly
the theory specified on the section 1.2.3.3
Example>> g11=tf([1 2],[1 2 1]);
g12=tf([1 -1],[1 5 6]);
g21=tf([1 -1],[1 3 2]);
g22=tf([1 2],[1 1]);
G=[g11 g12; g21 g22];
A=rga(G)
A =
1.0213 -0.0213
-0.0213 1.0213
2.2.6 nyqmimo
Syntaxnyqmimo(G)
Description
nyqmimocomputes the Nyquists Diagram based on the type of transfer function at theinput. nyqmimodistinguishes between transfer functions with singularities at the origin,
proper, strictly proper and strictly improper transfer functions, based on that structure, it
maps the Nyquists Diagram according to the Nyquists Contour. nyqmimo is capable
of computing the Nyquists Diagram for SISO and the Generalized Nyquists Diagram
for MIMO systems.
8/11/2019 MIMO Toolbox
21/25
MIMO Toolbox
- 18 -
Example 1>> G=tf([1 25],[1 5 3 -9 0]);
nyqmimo(G)
Example 2
>> den=1.25*conv([1 1],[1 2]);g11=tf([1 -1],den);
g12=tf([1 0],den);
g21=tf([-6],den);
g22=tf([1 -2],den);
G=[g11 g12;g21 g22];
nyqmimo(G)
2.2.7 m_circles
Syntaxm_circles
Description
m_circlessuperimposes the M circles of magnitude -2dB to 20dB. This function is
useful to measure the gain margin on a Nyquists Diagram.
8/11/2019 MIMO Toolbox
22/25
MIMO Toolbox
- 19 -
Example>> G=tf(1,[1 2 1]);
>> nyqmimo(G)
Verifying for sigularities on the origin...
Setting frequency range...
Mapping...
Plotting...
>> m_circles
2.2.8 icdtool
Syntaxicdtool(G)
Descriptionicdtool is a GUI designed to help the user in the task of designing controllers for a
2 2 MIMO system with under the Individual Channel
Design Scheme.
By default, icdtool calculates ( )s , when just loaded, icdtool will not load the
default controller. The controller will only be loaded and all the proper calculations
performed after the user has clicked on the UPDATE CONTROLLERS button. If the
user doesnt know entirely the behavior of the system, it is recommended that they load
a unitary gain proportional controller, in that way, the user will be able to analyze both,
( )s and the diagonal elements of the system, ( ) ( )1,1 2,2,g s g s . It is possible to load a
proportional controller by clearing the poles and zeros entries.
8/11/2019 MIMO Toolbox
23/25
MIMO Toolbox
- 20 -
2.2.9 gershband
Syntaxgershband(G) Gershgorin bands of G
gershband(G,v) Gershgorin bands and Nyquist Array of G
Description
gershbandcomputes the Gershgorin Bands of a n n MIMO system along with the
Nyquists Array.
Example>> g11=tf([1 2],[1 2 1]); g12=tf([1 -1],[1 5 6]);
g21=tf([1 -1],[1 3 2]); g22=tf([1 2],[1 1]);
G=[g11 g12; g21 g22];
gershband(G,v);
8/11/2019 MIMO Toolbox
24/25
MIMO Toolbox
- 21 -
2.2.10 arrowh
SyntaxArrowh(x,y,color,size,location)
Description
arrowhdraws a solid arrowhead in the current plot
Author: Florian Knorn
Email: [email protected], [email protected]
Homepage: http://www.florian-knorn.com/
8/11/2019 MIMO Toolbox
25/25
MIMO Toolbox
3. References
[1] Kailath, Thomas, Linear Systems, Prentice Hall, 1980, pp. 390-392, 443-450[2] Maciejowski, J.M., Multivariable Feedback Design, Addison-Wesley, 1989,
pp. 37-71
[3] Goodwin, Graham C., Graebe, Stefan F., Salgado, Mario E., Control System
Design, Prentice Hall, 2001, pp. 653-671
[4] Nise, Norman S., Sistemas de Control para Ingeniera, CECSA, 2002, pp. 614-
635
[5] Ogata, Katsuhiko, Ingeniera de Control Moderna, Prentice-Hall, 2003, 523-
566
[6] Carlos E. Ugalde-Loo, Eduardo Licaga-Castro, Jess Licaga-Castro, 2x2
Individual Channel Design MATLAB Toolbox Proceedings of the 44th IEEE
CDC, pp. 7603-7608
[7] J. Liceaga, E. Liceaga and L. Amzquita, Multivariable Gyroscope Control byIndividual Channel Design, Control Systems Society CCA, pp. 110-115, 2005
[8] E, Liceaga-Castro and J. Liceaga-Castro, Submarine depth control by
individual channel design, Proceedings of the 37th
IEEE CDC, e, pp. 3183-
3188, 1998
[9] J. Licaga-Castro, C. Ramrez-Espaa and E. Licaga-Castro, GPC control
design for a Temperature and Humidity Prototype using ICD anlisis,
Submitted for publication.